The invention relates to a casting component, in particular for a combustion engine of a motor vehicle, as well as a casting core for such a casting component. Furthermore, the invention relates to a method for the production of such a casting component As well as a method for the production of a casting core for such a component.
A casting component in the form of a cylinder crankcase and a method for the production of such a casting component can be gleaned as known from DE 10 2007 023 060 A1, wherein the production of a water jacket of the cylinder crankcase, designed as a cavity, occurs using a plurality of lost casting cores. More precisely, these casting cores are respective salt cores which are attached to a so-called cylinder liner in a preceding method for the guiding of respective pistons. After the molding of the cylinder liner during the production of the casting component, in a subsequent method, the respective salt cores, which consist of a water-soluble salt, are correspondingly rinsed out. Due to the lost casting or salt cores, the open cavities of the water jacket for cooling the cylinder crankcase are consequently formed.
The object of the present invention is to create a casting component and a casting core as well as a method for the production of such a casting component or of such a casting core, by means of which an increased strength or stiffness of the casting component can be achieved in the respective cavity formed by the casting core.
This object is solved according to the invention by a casting component as well as a casting core. Furthermore, this object is solved by a method for the production of a casting component or of a casting core.
In order to create a component which has an improved strength or stiffness in the region of the respective cavity, according to the invention it is provided that a porous metal body molded in the cavity is formed by the casting core. For this purpose, a casting core is used which is cast from a metal or a metal alloy together with a salt, in particular a crystal salt, or the same is processed. In particular, aluminum or an aluminum alloy, for example based on AlSi7, is thereby suitable as a metal or metal alloy. As included in the scope of the invention, however, it must be considered that other metals or metal alloys can also be used.
The porous metal body is generated by the salt from the lost casting core being rinsed out, in particular after the casting process of the casting component. An aqueous salt is preferably used here such that the salt can be washed out by rinsing with water. Then, the respective pores of the sponge-like, porous metal body are formed by the salt crystals or salt grains which are dissolved out. Overall, a porous metal body therefore results, by means of which the cavity generated by the casting core is at least partially filled. Due to this filling of the cavity, a structural reinforcement of the casting component and therefore a higher stiffness or strength results in this region. As a result, a weight saving can hereby also be achieved in the respective casting components as, due to the stiffening or reinforcement by means of the porous metal body, the respective walls surrounding the cavity can be dimensioned to be correspondingly smaller or thinner.
In a further advantageous embodiment of the invention, the casting component has at least one rinsing opening of the cavity which is open outwards, via which the salt is able to be rinsed out of the casting core for the formation of the porous metal body. In other words, according to the invention it is provided to insert the casting core into a casting tool, preferably as a semi-finished product with the salt still received therein, and to form the corresponding cavity by at least partial recasting or casting on with the casting material of the casting component. The rinsing out of the corresponding salt then occurs, for example, substantially only afterwards. The rinsing opening can be designed in such a manner that it is accessible directly after removal of the casting component from the casting tool, and that the salt can therefore be washed out directly after the casting process. Alternatively, the casting core can be completely recast such that firstly a (milling) processing of the casting component for partial exposure of the casting core (and therefore for the creation of the rinsing opening) must take place before the salt of the casting core can be washed out.
As is included in the scope of the invention, however, it must be considered that the salt can also be dissolved out of the respective casting core at least partially, even before the casting process. This is conceivable, for example, if, as is described below, an outer layer of the casting core is to be roughened for improved connection to the casting material of the casting component or if individual partial regions of the casting core or of the porous metal body can no longer be rinsed in connection with the casting process.
A further advantageous embodiment of the invention provides that the cavity within which the porous metal body is arranged is formed to guide a medium, in particular a coolant for the combustion engine of a motor vehicle. Such porous metal bodies in particular have the property of, on the one hand, stabilizing the cavity very well, however, on the other hand, having a sufficient permeability, such that a medium can circulate, for example cooling water or similar for the combustion engine of a motor vehicle.
In a further embodiment of the invention, the porous metal body and the casting component have materials or alloys having either at least substantially the same properties or, however, having different properties, in particular different thermal expansion coefficients. If the two respective alloys have at least substantially the same properties or these are at least substantially identical, then this has the advantage that a particularly good integration of the porous metal body into the respective casting component results. In particular, hereby, for example, tensions or similar within the casting component can be prevented and a good connection between the metal body and the casting component can be ensured. On the other hand, it can be advantageous if the alloys of the casting component or of the metal body are different. In particular, if the two alloys have different thermal expansions, a particularly favorable interlocking of the metal bodies within the casting component cavity can, for example, hereby be achieved.
The advantages referred to above in connection with the casting component according to the invention apply in the same way to the casting core.
In a further embodiment of the invention, regions within the casting core are provided with different metal proportions or salt proportions. Due to a corresponding variation of the metal or salt content, a corresponding variation of the porosity, size of the respective pores or similar can be generated in order to hereby influence, for example, the stiffness and strength of the metal body and of the casting component.
The advantages described above in connection with the casting component according to the invention and the associated casting core apply in the same way to the method for the production of a casting component.
In an advantageous embodiment it is thereby provided in the invention that the outer layer of the casting core is treated before the molding into the casting material of the casting component. For example, a corresponding coating of the casting core can be provided in this case in which, for example, less salt or, however, also more salt is provided than in an average region. Potentially, a roughening or structuring of the outer skin or outer layer of the casting core can also occur in order to achieve an improved interlocking of the casting core or of the metal body within the casting material of the casting component. For example, it is therefore also conceivable to roughen the outer layer of the casting core in that the corresponding salt is dissolved out already in this region before the casting of the casting component.
The advantages referred to in connection with the casting component according to the invention or the associated casting core as well as the corresponding method for the production of a casting component apply in the same way to the method for the production of the lost casting core.
Further advantages, features and details of the invention result from the subsequent description of a preferred exemplary embodiment as well as by means of the drawings.